Patent Literature 1 discloses a digital-to-analog conversion circuit which performs digital-to-analog conversion by using redundant digital-to-analog conversion devices. According to the background art of Patent Literature 1, the digital-to-analog conversion circuit is used in delta-sigma analog-to-digital converters. An RTZ or NRTZ waveform is employed as an output waveform of the digital-to-analog conversion circuit.
Patent Literature 2 discloses a D/A converter which converts an audio signal (1-bit digital signal) to an analog signal. According to the background art of Patent Literature 2, an RTZ waveform is employed as an output of the D/A converter.